You will get lots of opinions on whether the CHL (UHL, WCHL, etc) and ECHL were at the same level or not. Since there is no real agreed upon definition it is impossible to be definitive. As a fan of an ECHL team, who never watched CHL games I can say that the Royals would occasionally sign players out of the CHL and occasionally former Royals would sign in the CHL, and there was a difference. Top scorers from the CHL would end up on the third line or used as a fill in/healthy scratch in the ECHL and ECHL third liners who were mostly used as defensive forwards/PK were top line players in the CHL, putting up 20-30 goals a season. Obviously this is a small sample size, because I only saw a handful of players make this transition, and individual performance can vary from year to year even playing in the same league. My opinion is that the ECHL and CHL were both "AA", but the talent level was higher in the ECHL overall.
The SPHL and it's predecessor leagues were definitely a step below. I disagree that they are below "A" level though. Top end SPHL players can and do end up earning a spot in the ECHL. Although a first line forward or top pairing defenseman in the SPHL is going to be a 10th forward or 7th defenseman in the ECHL in most cases. Goaltenders are different of course because there are less positions available, and often times contract status takes precedence over skill/talent.
My opinion:
- Original IHL AAA (at least during the time it was competing with the AHL to sign the same players)
- WPHL (Western Profesional HL) AA
- ACHL (Atlantic Coast HL) A
- WHA2 (World Hockey Association 2) A